After the Mantis Fist school attacks the Eagle’s Claw school and leaves their teacher for dead, the dying master passes over his senior student, Chen Tien Chun, to anoint his second most senior pupil, Lee Cheh, as new master. Dejected, Chen joins the Mantis Fist school and wins the affection of his new master’s daughter, while his former schoolmates plot revenge.

By a strange twist of fate, dutiful Hong Kong policeman Dan saves the life of the leader of a violent gang of armed robbers. When they commit another crime, Dan is determined to put an end to their activities. He works with the leader, whom the gang had betrayed, to engineer a plan to wreak havoc within the gang and let the gangsters kill one another. But it becomes increasingly obvious to Dan and to his colleagues that Dan is suffering from a severe mental disorder, and Dan finds that instead of upholding the law as a righteous police officer, he has now become a fugitive wanted for murder.